Fixes issues from #714

Slots were not triggering a save when items are added/removed from the slot. To fix this I changed saving from the Slot#onSlotChange() to Slot#onSlotChanged(), this bug was probably introduced in the port to 1.7.

When the player removes the Alchemical Bag from there inventory when the Alchemical Bag GUI was open (by tossing it on the ground) the GUI did not close. This has been fixed by hooking into the onItemTossEvent and closing the GUI when the 'parent' of the container was tossed.